A touch screen display is a device that can detect an object in contact therewith or in proximity thereto. The touch screen display includes display layer covered with a touch-sensitive matrix that can detect a user's touch by way of a finger or stylus, for example. Touch screen displays are used in various applications such as mobile phones, tablets, and smartwatches. A touch screen display may enable various types of user input, such as touch selection of items or alphanumeric input via a displayed virtual keypad. Touch screen displays can measure various parameters of the user's touch, such as the location, duration, pressure, etc.
One type of touch screen display is a capacitive touch screen. A capacitive touch screen may include a matrix of conductive rows and columns overlaid on the display layer forming mutual capacitance sensors. In mutual capacitance sensors, a mutual capacitance at the intersection of each row and column of the matrix may be sensed. A change in mutual capacitance between a row and a column may indicate that an object, such as a finger, is touching the screen or is in proximity to the screen near the region of intersection of the row and column.
In some electronic devices, a capacitive touch screen may have multiple layers of mutual capacitance sensors in a stacked arrangement, with one layer being used to determine the X and Y coordinates of a touch location, and with another layer being used to determine the force or pressure with which the object making the touch presses against the capacitive touch screen. These different sensing layers may contain different numbers of mutual capacitance sensors. Due to the different number of mutual capacitance sensors, the pitch of these different sensing layers is not equal, which may adversely affect the accuracy of acquired touch data, in that data of a given touch event as acquired by the different sensing layers may not be cross correlated between those different sensing layers.
Thus, a need exists within the art for techniques by which touch data collected from different mutual capacitance sensors can be cross correlated, at the time of acquisition.